A DNA Structure Containing AgI-Mediated G:G and C:C Base Pairs

Metal-mediated base pairs have been extensively utilized in many research fields, including genetic-code extension, novel therapeutics development, and nanodevice design. Compared to other cations, Ag-I is more flexible in pairing with natural base pairs. Herein, we present a DNA structure containing two C-Ag-I-C pairs and the first reported G-Ag-I-G pair in a short 8mer DNA strand. This structure not only provides detailed insight into these Ag-I-mediated base-pairing patterns in DNA, but also represents the first nonhelical DNA structure driven by heavy-metal ions, thus further contributing to the structural diversity of DNA. This unique complex structure is highly sequence-dependent, thus implying functional potentials as a new DNA aptamer that can bind and recognize silver ions. These results not only advance our understanding of the interactions between Ag-I and nucleobases, but also provide a unique structural component for the rational design of new DNA nanodevices.